It is known that frying or boiling a large quantity of food products in the field of professional catering is done using fryers or boilers provided with a pan which contains the cooking liquid and in which, once the latter has reached a suitable temperature, the food products to be fried or boiled are immersed, generally vegetables, pasta, fresh pasta, fish, meat but also confectionery products or other.
The pan is lapped on the outside by free flames usually produced by gas burners housed in a combustion chamber which surrounds the pan, which rapidly bring the liquid to the desired temperature.
Generally, a pressure fan is disposed upstream of the combustion chamber, to introduce therein the combustion air needed. The functioning of the fan is usually calibrated or adjustable to determine a balanced ratio of air/combustion gas in the combustion chamber so as to have the correct combustion.
The gas burners have a typical elongated structure and disposed below and at the two sides of the pan. Typically, a flue is provided disposed in a rear zone, so that the flames issuing from the gas burners tend to flow to the rear.
The mass of food to be fried or boiled is disposed in suitable baskets which, once filled, are immersed in the boiling liquid, which is usually oil for frying or water.
An apparatus for frying or boiling food products is described in the application WO-A-03/011092.
Before they are immersed into the boiling liquid, the food products are generally at a much lower temperature than that of the boiling liquid, and their immersion causes a sudden reduction in the temperature of the liquid, which must be immediately compensated by the action of the gas burners to bring the temperature back to boiling or frying point.
Consequently, a known limitation of the apparatuses in question is the consumption of gas to return the temperature to boiling or frying point.
Another limitation of known apparatuses is the sometimes unsatisfactory transmission of the heat generated by the flames to the liquid contained in the pan, which implies a slow heating and return to the desired temperature for frying or boiling. To overcome this limitation, it may be necessary to make a pan of metals with a high heat conduction, with the risk, of polluting the fried or boiled food with salts or metal ions which could derive from contact of such metals with the flames.
Document GB-A-2.323.023 describes a known apparatus to fry food products which comprises a pan for frying formed by an upper part and by a lower well. The latter has a side wall heated by a gas heater and is asymmetrical around an axis passing through the center of the upper part.
Document U.S. Pat. No. 4,848,318 describes another known apparatus to fry food products which comprises a pan to heat the oil, which has a central well and burner means disposed at the sides of the well.
Document U.S. Pat. No. 6,073,541 describes another known apparatus for boiling food products in water which comprises a basket for the food, a container for boiling, a combustion chamber with burners disposed at the lower part and a flue for the extraction of the fumes.
One purpose of the present invention is to obtain a pan-type apparatus for frying or boiling food products which overcomes the disadvantages of the state of the art and which, in particular, has a quicker heating capacity compared to the state of the art.
Another purpose is to reduce the consumption of gas by the gas burners which emit the heating flames.
Another purpose is to obtain a greater uniformity of temperature of the liquid in the pan.
Another purpose is to prevent the emission of noxious substances into the liquid in the pan.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.